Why you Shouldn't Use Optical Media for Backups

CDs and DVDs are Unreliable

Even the best branded media under optimal storage conditions will not last longer than a couple of years. At best, burned CDs last 10 years, while DVDs only last three years. Under real-life conditions, which are usually far off from the optimal, you can expect maybe a couple of years for CDs and less than a year for burned DVDs. The main alternative to CD backups, while a little more expensive, is external hard disk backup.

Even if your information is short-lived, the rather short life expectancy of optical media is something you need to consider.

CDs and DVDs are sensitive to light, heat, cold, scratches, and mechanical force, stress, and shock. In addition, bit errors can occur randomly even under perfect storage conditions.


Optical Media is Slow

The burn rates may have increased quite a bit in the past; however, nothing beats the speed of hard drives. Think about the time you waste burning DVDs: selecting the folders and files, switching DVDs, filing DVD, labeling them, etc.

The burn speed is at best 22x (29MB/s) which is still far behind an eSATA external hard drive's 150MB/sec. Also, we shouldn't forget to mention the extremely fast random access speed of >10ms for hard drives.

If you wanted to back up 1TB of information, an external eSATA hard drive could finish the job less than 2 hours. On the other hand, you would need to burn about 218 DVDs to back up 1 TB....


Optical Media Offers only Limited Capacity

Switching media when burning DVDs and CDs requires manual labor. Someone has to check on the system and switch from CD to CD. A tape or hard drive backup system doesn't switch volumes; hence, reduces manual labor. In addition, the complete backup is on one external hard drive when backing up to USB or eSATA hard drives.

CD and DVD backups require disk spanning and hence a much more complicated to handle. In addition, most backup tools require all CDs in order to restore even a single file. Hence, if your backup spans 10 DVDs you have a disk failure risk that is 10 times higher than when using just a single DVD.